Antimicrobial materials such as fabrics, fibers, polymers and even children's toys have become increasingly popular due to public concerns over epidemiological diseases and pathogens. With respect to antimicrobial fabrics, domestic and international markets have grown significantly as a result of public awareness of these potential threats (see, Center for Disease Control and Prevention, Infection Control and Biosafety, Medical Data International. Report #RP-701530, 1992; and A. J. Rigby, et al., Fiber Horizons, December 1993, 42–460). Antimicrobial clothing can be used in medicine as well as other institutional uses for such applications as, surgeon's gowns, caps, masks, patient drapes, bandages, wipers and cover cloths of various sizes.
Although the demand for antimicrobial fibers is high, few of such fibers are available, especially ones that are effective against a broad spectrum of bacteria and, which are effective after multiple machine washes. Research and development of durable functional fibers has been active in recent years, with new methods of incorporating antibiotics as bactericidal agents into polymers being advanced.
There are two major pathways to chemically achieve durable antibacterial effects. In one pathway, the slow-releasing of biocides through contact with the processed fabrics is employed. In this pathway, a pathway widely used around the world, sufficient chemical agents are impregnated onto the fibers by either chemical or physical methods. Thereafter, the biocides are slowly released from the processed fabrics into the media, thereby contacting and inhibiting the growth of microorganisms. Unfortunately, such chemical agents can be washed away easily if they are not covalently impregnated onto the surface of the fabrics. Moreover, the antibacterial functions are non-regenerable.
In the second pathway, a more innovative technology is employed which involves chemical modification of fibers with biocidal or potential biocidal compounds, wherein the antibacterial properties of such compounds are regenerable with a simple washing. The potential antibacterial groups can be rendered biocidal after washing with certain common chemicals, such as diluted bleaching solutions. U.S. Pat. No. 5,882,357, filed Sep. 13, 1996, describes durable and regenerable cellulose materials by using an innovative chemical finishing method. In that invention, treatment of cotton and polyester/cotton fabrics were finished by hydantoin derivatives, and biocidal properties were conferred by washing the treated fabrics with a chlorine laundry bleach. Chlorination of amide and imide bonds in hydantoin rings produce biocidal N-halamine sites. The N-halamine return to their precursor forms when the sites are exposed to microorganisms. The biocidal properties of the fibers can then be regenerated by using chlorine bleach. The major advantages of this chlorine regenerable finishing method are its durability, convenience and economy.
N-halamine chemistry, however, is not applicable to colorized fabrics. The use of chlorine bleach decolorizes fibers. Thus, a non-bleach regenerating agent would be desirable for certain applications, especially for colored materials.
In view of the foregoing, there exists a need in the art for durable and regenerable microbiocidal fibers that do not pose environmental concerns and are not limited to white fabrics. The present invention remedies such need by providing, inter alia, environmentally friendly, durable and regenerable microbiocidal colored fibers. Peroxycarboxylic acids have been applied on natural materials, and materials derived from natural materials. These compounds are soluble in water, so an aqueous finishing process is adopted. The chemicals were padded on fabrics, and then dried and cured at elevated temperatures. The biocidal properties of finished fibers have been evaluated against bacteria such as Escherichia coli. and Staphylococcus aureus. 